[Microassay of plasma isoniazid by high performance liquid chromatography]

The authors propose a technique for the assay of isoniazid (INH) using inverted phase high performance liquid chromatography. The plasma INH is condensed with cinnamic aldehyde after deproteinization with trichloracetic acid. The authors confirmed the absence of interference with other anti-tuberculous drugs. The technique is very fast and simple to perform.